Hi,
Currently we are using apache http server as our web tier and evaluating another options.

Our app tier cluster is stateful and each session is handled by only a single app server. Web tier takes care of stickiness by the session. The stickiness is implemented by cookie (part of a session id has a hint to the corresponding app node).

Current architecture has a limitation when multiple clients need to make operation on specific session (not only browser).
The problem arise when an app server crashes and the request is forwarded to another app node. In this case all clients must be synchronized (updated) with that new mapping (session --> new node) in order to make sure web tier will forward their requests to correct app server.

One possible solution is to avoid client awareness of the session->app mapping and to give that responsibility to the web tier. In this solution all web nodes must be synchronized on the same mapping (session -> app) and forward requests using that data (instead of cookie). In case an app node is crashed web server will recognize it, choose new app server and update that mapping so all other web servers will be aware of new mapping and forward requests correctly (all client will be served correctly without the need to synchronize them)

Does Resin has solution for our requirements?
Any ideas how to solve the described problem in elegant way?